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Is Your Gmt-900 Truck Or Suv Using Oil


Is your GMT-900 using oil  

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Great info there - I appreciate it. The truck sits alot, so Signature Series probably isn't the best choice. Don't think there's any good choices for something that takes short trips and sits parked for weeks on end.

 

As far as my truck goes, "we shall see" is all I can say. No matter what happens, I'll be running this truck until the thing just falls apart. Never buying another new one, and have no plans to buy another truck at the moment. When/if the engine lets go, I'll cross that bridge when the day comes. Hopefully it's 5 years from now, when it's exempt from emission testing. Will make my repair choices much easier & cheaper. I'll keep fixing this turd until there's nothing left to fix.

Edited by Jsdirt
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First off, I feel that not only me, but others that have read all of the rants on how the 5.3 AFM engines have been incorrectly labeled as being mechanically prone to failure has been over blown. Sure

I've been watching this oil usage issue a long time now. Sick of it. My '96 5.7 used NO oil! And I could get 20 mpg highway. Extended cab, loooong bed too. Dagnabbit, GM is running customers away.

Yep - they've forced alot of manufacturers to cut corners just to survive.   The EPA has done more harm to this nation the past 20 years than good. Another gigantic, bloated, goverment bureaucracy t

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Great info there - I appreciate it. The truck sits alot, so Signature Series probably isn't the best choice. Don't think there's any good choices for something that takes short trips and sits parked for weeks on end.

 

As far as my truck goes, "we shall see" is all I can say. No matter what happens, I'll be running this truck until the thing just falls apart. Never buying another new one, and have no plans to buy another truck at the moment. When/if the engine lets go, I'll cross that bridge when the day comes. Hopefully it's 5 years from now, when it's exempt from emission testing. Will make my repair choices much easier & cheaper. I'll keep fixing this turd until there's nothing left to fix.

 

 

So exactly what has been broken, replaced repaired on this truck? I mean "cowpie" seems to not even be worried......

Edited by mookdoc6
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Keep in mind, GM uses a LOT of copper in the form of brass, especially in cam bearings. High CU is not really that uncommon in GM engines. I have seen it in many engine oil analysis reports from relatively newer engines and ones that have racked up some serious miles and the engines are just fine. Only when there is corresponding elevated levels of tin and lead (the other components in cam and rod bearings) is that indicative of a problem. Elevated CU by itself may not mean much. Many sources from bearings I mentioned to oil coolers. And some oil additive packages will amplify CU leaching.

 

One of the big problems we as owners of cars and light trucks have, is that the OEM is not forthcoming with condemnation limits on wear metals in oil samples. We easily can get those for commercial equipment and heavy truck engines. Without knowing what the max limits on wear metals as established by the OEM itself, we are just wandering around in the dark, and probably over reacting to what some lab considers elevated wear metals. Many commercial engines do not reach max limits until FE counts get to 200 ppm. While 52 does seem disconcerting, it has to be factored along with other wear metal ppm to see if it is something to worry about. FE and CU are from totally different sources and elevated levels of each of them has little to do with each other. If I was seeing elevated levels of aluminum and chromium along with Iron, I might be concerned.

 

And without multiple UOA reports to track trend lines and patterns, it is a crap shoot to make a determination based on one oil sample.

 

On that report, TBN has gotten to the level I would change it out. Without doing a TAN analysis with TBN, the common practice in commercial industry circles is that when TBN reaches 1/3 of what it started at, it is time to get the oil out. TAN (total acid number) which rises over time, and TBN levels which deplete over time in addressing the acids, on average will meet at about 1/3 of the starting number for TBN. if the oil started with 10 TBN, then 3.3 TBN is all the lower I would let it go. If the oil started with 12 TBN like many of Amsoil's SS lineup, then the oil has dropped below 1/3, which would be 4 TBN. It is possible in that situation that acids are causing the elevated FE and CU. I said it is possible, not that it is a fact.

 

Will probably get some arguments against this, but there is tons of resources out there that will support my comments. So don't go shooting the messenger. Do your own research and find out.

I had 200 ppm of copper in the UOA from my 6.0l at about 7500 miles (the truck was new). It remained elevated many miles later, but I've only did those two UOAs.

 

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Good to know, Steve. Thanks

 

 

 

 

So exactly what has been broken, replaced repaired on this truck? I mean "cowpie" seems to not even be worried......

42 miles on the clock, brakes pulsated - right off the showroom floor. 6+ warranty trips to dealer never fixed it.

 

4x4 switch was frigged up also right out of the gate. Dealer kicked can down the road until out of warranty, and I ended up eating it.

 

At around 2k miles, the interior began to squeak an rattle worse than any of my 20- 30 year old vehicles.

 

Also around that same time, the driveline developed a "clunk" on light throttle 1-2 upshifts that has got progressively worse as the miles rack up.

 

Lower ball joints failed at 38k.

 

Around 50k my front differential started leaking out the axle seals.

 

At 50k, engine started burning oil when pushed. (piston rings)

 

Also at 50k, upper ball joints, BOTH hub bearings, and one strut failed.

 

Currently, it failed emissions because for some unknown reason, the o2 & EVAP monitors refuse to run, no matter how much I drive it.

 

 

 

Only 91k on the truck! I've driven cars that I bought with over 200k on the clock that were 20 years old that didn't have HALF these problems. What a f***ing waste of money!!!

Edited by Jsdirt
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I had 200 ppm of copper in the UOA from my 6.0l at about 7500 miles (the truck was new). It remained elevated many miles later, but I've only did those two UOAs.

Sent from my SAMSUNG-SM-G900A using Tapatalk

I had elevated levels of CU in my 2013 5.3 and my current 2015 6.0. The latter is a great vehicle and the engine is doing great. CU has come down over time, but still substantial. After looking at how GM has a love affair with brass in their engines, it all made sense.

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I had elevated levels of CU in my 2013 5.3 and my current 2015 6.0. The latter is a great vehicle and the engine is doing great. CU has come down over time, but still substantial. After looking at how GM has a love affair with brass in their engines, it all made sense.

When I did my first 6.0l UOA in 2012, it immediately caused me concern because it wasn't like any UOA I had ever seen. In my limited experience, in the Cummins it meant oil cooler failure was starting. A quick Google search in 2012, and a lot of Vette owners were reporting the same and they indicated it was from the wrist pin retainers? Been a while since I looked that up...120k miles and engine runs perfect.

 

One thing I will point out that we often forget is that a UOA is a used OIL analysis. While it may give some indication of engine condition, at the end of the day it is still an oil analysis, not an engine analysis.

 

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Definitely a great point. BUT ... given the history of my vehicle, it's cause for concern.

 

Like I said, I'm running this turd until it grenades, so one way or the other doesn't much matter.

 

My first 2 oil analysis' were showing high levels of aluminum and iron, suggesting piston, rings, and cylinder wear. That was backed up by excessive oil consumption, only when I let the engine pass 3,500 RPM on hills while towing.

 

If I keep it under 4k, she'll go 6k on a quart. If I set the cruise control and let her downshift to 5k, she'll burn a quart in 300 miles. Definitely a piston ring issue there.

 

I've had alot of vehicles over the years, mostly old, with alot of miles, and NOT ONE of them used oil like this. Only one car leaked close to that - my '83 Skylark. POS FWD 4-banger.

Edited by Jsdirt
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  • 2 weeks later...
On 8/9/2017 at 3:14 PM, scogeb said:

I've talked to my mechanic and the dealer's mechanic and my plan is to run 1,000 miles and see what the oil consumption is and then get the Range module and run another 1,000 miles and see what it is then. I'll post back with the results in a few months. Thanks!

***UPDATE***

After 1,000 miles, I have had to add 1 quart of oil.  I just installed the Range yesterday, so I will report back after another 1,000 miles.

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On 10/27/2017 at 11:04 AM, scogeb said:

***UPDATE***

After 1,000 miles, I have had to add 1 quart of oil.  I just installed the Range yesterday, so I will report back after another 1,000 miles.

Am guessing the Range (turning off AFM) will stop about 7/8 of your oil usage, unless you have more mechanical problems.  At least, that has been my experience. 

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On 10/30/2017 at 3:57 PM, MaverickZ71 said:

Am guessing the Range (turning off AFM) will stop about 7/8 of your oil usage, unless you have more mechanical problems.  At least, that has been my experience. 

That would be awesome!  I'm still getting the white puff of smoke out the exhaust on startup though after I drive it pretty hard/fast (80mph).  I'm thinking I need to get the valve cover replaced, but I want to wait and see how the Range impacts oil consumption first.

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I'm going on 3 years with the Range. Did nothing for oil consumption in my case - my issue is ring sealing, not AFM issues (yet ...). Would still buy it again though, just to hopefully delay the inevitable AFM lifter collapse.

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  • 4 weeks later...

So, just FYI, I also have a 2016 z71 5.3 AFM crewcab long bed work truck that I have put almost 20k in miles on it driving highway/city, heavy sourthen California traffic, Mountain roads, and some off-roading. I try to max out v4 mode as much as I can to save gas. I have had two dealer oil changes so far and checked the levels. No issues on this truck so far.

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